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Massachusetts Water Resources Authority
Frederick A. LaskeyExecutive Director
20 Years of Change: Boston Harbor
Pollution Abatement Project Timelines
Andrea Rex
Outfall Monitoring Science Advisory Panel
June 10, 2008
2
Timeline: Starting conditions
• Two failing primary treatment plants discharged total 350 million gallons/day to harbor.
• Digested sludge discharged in northern harbor. • 84 CSOs discharge 3 billion gallons annually
during wet weather
1986 Federal judge ordered schedule to construct new Deer Island Treatment Plant and related facilities.
3
Timeline: Early changes
1988-1991• Upgrades old DITP, including
improvements to disinfection.
• Sewage scum land-filled instead of being discharged into the harbor.
• 1991: End of sludge discharges into the harbor; sludge is made into fertilizer pellets.
• CSO discharges cut in half to 1.5 BGY
4
Timeline
• Improved pumping capacity at DITP decreases CSO further, most dramatic in Charles River
• Start-up of secondary treatment at DITP 1997
• Nut Island Treatment Plant flows transferred to DITP.
• NITP decommissioned 1998, end of discharges to the southern harbor!
1992-1998
5
September 2000September 2000
Start-up of new 9.5 mile-long outfall. DITP effluent discharged into Massachusetts Bay
End of effluent discharges to Boston Harbor
6
TSS discharges
Solids in MWRA Treatment Plant Discharges 1990-2007
0
20
40
60
80
100
120
140
160
180
90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07
Tons
per
day
Deer Island Nut Island Sludge
1998Nut
Island transfer
Dec 1991
End of sludg
e
Sept 2000
offshore
7
Metals in MWRA Treatment Plant Discharges 1991-2007
0
100
200
300
400
500
600
700
91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06 07
Year
Ave
rag
e p
ou
nd
s p
er d
ay d
isch
arg
ed
Silver
Nickel
Chromium
Lead
Copper
Zinc
Dec 1991
End of sludg
e
1998Nut
Island transfer Sept
2000 offshore
9
After 2000, WWTPs no longer significant source
CSO projectsCSO projects
20002000• Constitution Beach (Winthrop Bay)
CSOs ended.
• Several CSO hydraulic relief projects.
• Cottage Farm CSO facility upgrades.
• Neponset River sewer separation, CSOs closed
20012001• Dorchester Bay CSO facility upgrades
• Prison Point (mouth of Charles) facility upgrade
• Somerville Marginal (mouth of Mystic) upgrade
• Chelsea Relief Sewer projects
10
CSO Projects
20062006• Stony Brook (large discharge to Charles River) sewer separation• South Dorchester Bay sewer separation• Pleasure Bay storm drain improvements
20072007• BOS019 CSO storage facility (Charlestown)• Union Park Detention and Treatment Facility (Fort Point
Channel): Stores 2MG for pump-back, treats remaining overflows• Fort Point Channel Sewer Separation and Optimization• Decommissioning of South Dorchester Bay CSO facilities (Fox
Point and Commercial Point)End of CSO discharges to South Dorchester Bay!
12
Summary: changes in size and location of loadings
Pre 1991
Sludge discharge ends
1991
1992-1998
New primary facilities DITP
1995
Upgrade to secondary
began 1997
1998-2000
Inter-island transfer
Secondary upgrades continue
2000-present Outfall transfer
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